# ---
# title: 594. Longest Harmonious Subsequence
# id: problem594
# author: Tian Jun
# date: 2020-10-31
# difficulty: Easy
# categories: Hash Table
# link: <https://leetcode.com/problems/longest-harmonious-subsequence/description/>
# hidden: true
# ---
# 
# We define a harmonious array as an array where the difference between its
# maximum value and its minimum value is **exactly** `1`.
# 
# Given an integer array `nums`, return _the length of its longest harmonious
# subsequence among all its possible subsequences_.
# 
# A **subsequence** of array is a sequence that can be derived from the array by
# deleting some or no elements without changing the order of the remaining
# elements.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: nums = [1,3,2,2,5,2,3,7]
#     Output: 5
#     Explanation: The longest harmonious subsequence is [3,2,2,2,3].
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: nums = [1,2,3,4]
#     Output: 2
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: nums = [1,1,1,1]
#     Output: 0
#     
# 
# 
# 
# **Constraints:**
# 
#   * `1 <= nums.length <= 2 * 104`
#   * `-109 <= nums[i] <= 109`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
